Determining main vent location

grantsweatshirt

Hello all, fascinated by the inner workings of steam heat and all the information this board has to offer. I took the building over just a few months ago and currently, I'm faced with uneven heating and lack there of in certain rads of my 7 unit building. The boiler is new but there weren't main vents installed when the system was replaced. I'm faced with the task of adding main vents but im unsure of the best location. For starters, I have two first floor units that carry the rads in the ceiling (the basement sits higher than these apartments). The end of those mains (two different mains) pipes directly into ceiling rads. See attached photos. Could I tap into the 90, add a nipple and place a gorton #2? I'll gladly provide more pictures if required, just starting conversation. Thank you all.

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JUGHNE

Does the building have a single or two pipe system for other radiator connections?

What is the piping configuration on the other side of the wall of these ceiling rads?

grantsweatshirt

the building has a two pipe system for all other rad connections. attached are some more photos of how the main is piped back to the boiler. also is a pic of the boiler itself and a crude drawing on how the mains feed elsewhere in the basement. thanks in advance

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grantsweatshirt

pic labeled #1 is the start of the piping on the other side of the wall

JUGHNE

Do all of the 2 pipe rads have a steam trap on the outlet?

How does the air get out of the ceiling rads? Do they have traps we don't see?

Or does anyone here think they could be condenser rad for the return?

grantsweatshirt

the ceiling rads and all other rads in the building are tapped with 1/8 angle vents. i could be mistaken by the two pipe system so ill provide you a picture of how the piping looks coming into the radiators on the 2nd floor and so on.

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EdTheHeaterMan

Is this a Paul system?

I just watched a video that mentioned that type system.

grantsweatshirt

I'm not familiar with the paul system. Yes, that is the same radiator. I believe they are both are 1-1/2" valves.

Steamhead

That was definitely a Paul system- good eye, @EdTheHeaterMan .

@grantsweatshirt , the Paul system used a jet-type exhauster to pull air from the radiators. Instead of a regular air vent, a special Paul vent was used which connected to these exhauster lines. In the rad pic you posted, you can see a small pipe coming up just to the left of the rad. That was the exhauster connection.

Hoffman still sells rad vents for this system:

https://www.nationalpumpsupply.com/401419-hoffman-model-3-steam-air-line-valve/

The Paul system is covered in chapter 15 of @DanHolohan 's excellent book "The Lost Art of Steam Heating":

https://www.heatinghelp.com/store/detail/the-lost-art-of-steam-heating-revisited

Also, to the left of the rad in that pic are three riser pipes coming up from the floor. They are, in order of decreasing size: Steam, Return, Air Line (exhauster).